This invention relates to self-building detergents and a method for their preparation.
Self-building detergents are useful in clothes cleaning, dish cleaning and the like.
Detergents and soaps precipitate out of aqueous solution if certain ions, such as calcium or magnesium, are present in high concentrations. Water with these ions present in sufficiently high amounts is known as hard water. Chelating agents are compounds which complex these detrimental ions in such a way that the ions are no longer available to cause the precipitation of detergents and soaps. It is known to use certain chelating agents called builders in conjunction with detergents and soaps to minimize or eliminate problems associated with their use in hard water.
Builders which have been used include phosphates, carbonates, borates, silicates and citrates. Problems existing with conventional builders include ecological contamination in some cases and lack of effectiveness in others. In addition, various problems exist with the use of separate detergent(s) and/or soap(s) with builders, such as separation of particles in the particulate cleaning powder before being mixed with water.
Mechanisms exist to circumvent the problems associated with using a separate builder. These mechanisms include depositing the builder and soap(s) and/or detergent(s) in a single particle or dissolving the builder and soap(s) and/or detergent(s) in a concentrated solution. However, component incompatibility, consumer preference for solid cleaning systems, breakdown of bleaching agents and high cost are factors which encourage a search for additional approaches to address these problems. One answer is to use a selfbuilding detergent which is a molecule which acts as a detergent as well as a builder. British Patent 1,404,054 describes a group of such self-building detergents. However, these self-building detergents disadvantageously have poor cleaning ability for cleaning clothes. Thus, what is needed is an effective self-building detergent which has good detergency over a wide range of water hardness.